Granulocytic sarcoma in a patient with essential thrombocythemia presented as acute spinal cord compression--case report and review of the literature.

Granulocytic sarcoma (GS) is a rare solid tumor of myeloid origin, which usually precedes or occurs concurrently with myeloid leukemia, or with other types of myeloproliferative and myelodysplastic disorders. Spinal affections of GS have been described but are uncommon, particularly in association with essential thrombocythemia. We present a case of a 75-year-old woman with a long history of essential thrombocythemia who developed 2 tumors: 1 in the bodies of T3 - 6 vertebras extending epidurally, and the other in the right frontal lobe, adherent to dura, thus, mimicking meningioma. The patient died because of massive pulmonary thrombembolia. Microscopical and immunohistochemical features of spinal and intracranial tumor samples obtained at autopsy were consistent with the diagnosis of GS with focal megakaryocytic differentiation. Clinicians and pathologists should be aware of this rare tumor being so diverse in its clinical presentation, as well as in microscopical and immunohistochemical features. Careful evaluation of morphology, in conjunction with immunohistochemistry for evidence of myeloid differentiation are required to avoid frequent errors in diagnostics of GS. The suggested panel includes chloroacetate esterase, myeloperoxidase, lysozyme, CD117, CD43, CD79a and CD3. Only early correct diagnosis will enable proper treatment which may be successful despite the highly malignant potential of GS.